Made up my mind about more HP, now a ?

I've decided I'll be moving up in hp on the Dart. One of my friends operates a machine shop, is a mopar-or-nocar guy, and has several operating engines in storage. I'm going to look at them and he has 318s, 360s, a 383, and a 440. One of his 318s is a stroked one he did for his old service truck and only has 5k on it(I like). On the other hand he has a 383 which is also appealling to me but I don't know how much harder it would be to fit it into my Dart. Opinions???

Not really wanting to run headers and monkey with adapters or cutting up the drive line.